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I would phrase it sligthly a different way. How about slightly oversaturated and the other parameters correct? I could live with a slight bit of oversaturation if the luminance and gray scale measured well. At the price of the projector, I'd consider it a reasonable compromise. It might not be possible even allowing for some oversaturation to get the other parameters within an accurate range?

Well if you look at my green, it is still quite over saturated but luminance has already been badly affected. Correcting the Green saturation further just makes things worse. At what point do you say no more to luminance loss?

Well if you look at my green, it is still quite over saturated but luminance has already been badly affected. Correcting the Green saturation further just makes things worse. At what point do you say no more to luminance loss?

When it doesn't look right There are not that many situations where you have pure green only. Balance for the best look.

Does anyone know if this is likely a hardware limitation which is preventing bigger adjustments. That would be my first assumption.

Large adjustments to the video signal or processing can have very negative effects. These CMS adjustments are strictly processing. The hardware factor is the consumer industry's desire to compete with wide color gammuts.

On the Lumagen Radiance thread Tom Hoffman posted this, "I wonder if this approach would be useful? I know that the Crystalio folks have struggled with implementing a true saturation control to fix just these sorts of problems and have been unable to implement a control that affects color saturation that does not also substantially affect color brightness." Deja vu. Even with Lumagen actively working with the CMS of the Radiance, I believe that the range had to be doubled, that still was not enough to rein in green on the RS1, and then further increased.

I would phrase it sligthly a different way. How about slightly oversaturated and the other parameters correct? I could live with a slight bit of oversaturation if the luminance and gray scale measured well. At the price of the projector, I'd consider it a reasonable compromise. It might not be possible even allowing for some oversaturation to get the other parameters within an accurate range?

Again, you can more easily see color difference than you can see luminance. If you have the grayscale correct, you have a partial correction for the luminance because you are adjusting the Y for RGB to achieve White.

On the Lumagen Radiance thread Tom Hoffman posted this, "I wonder if this approach would be useful? I know that the Crystalio folks have struggled with implementing a true saturation control to fix just these sorts of problems and have been unable to implement a control that affects color saturation that does not also substantially affect color brightness." Deja vu. Even with Lumagen actively working with the CMS of the Radiance, I believe that the range had to be doubled, that still was not enough to rein in green on the RS1, and then further increased.

This was all new territory, I think Lumagen went through 3-4, if not more methods to get the Radiance CMS to actually work, however it is a very complex issue and has taken over a year to have a viable external CMS.

This was all new territory, I think Lumagen went through 3-4, if not more methods to get the Radiance CMS to actually work, however it is a very complex issue and has taken over a year to have a viable external CMS.

With Lumagen being much more sophisticated at this than JVC and apparently the other companies, my second assumption is that the chances of this implementation providing a viable internal CMS are low. Has anyone ever measured the scaler/RS2 package that JVC sell? Is it any more accurate than the internal CMS of the RS20? I guess a better question is, is the preset for accurate colors on that scaler the same as the performance of the THX preset on this one? THX might want to take their name off this one with users reporting that it is unuseable.

The figured the Lumagen might help a bit, but it throws secondaries out quite a bit (JVC CMS can correct a lot of the issues) and I wasn't that happy with the image quality afterwards. I decided to try again without and I'm very happy with the results. The trick is to play with the saturation, hue and brightness controls for each colour, they all affect each other in strange ways like upping the brightness on the green reduces the saturation .

I would say it depends on the Luminance error, the eye is much more sensitive to color than it is to luminance.

That's not quite correct. In fact, in side-by-side comparisons the eye is very sensitive luminance errors. Consider:

The first pair of reds offers an approximately 11% difference in saturation.
The second pair offers approximately an 11% difference in lightness. At least to my eyes, the difference is roughly comparable.

What I do think is true is that the eye is less sensitive to luminance errors with real program material because we have fewer visual cues as to what the proper level of luminance is supposed to be. On the other hand, we are more tuned to the proper levels of saturation and hue of natural objects.

Can someone comment on the effects on other aspects of the image when using the CMS processing (eg. does brightness suffer significantly, does it add other distortions like banding)? If there are negative side effects of using the CMS, is it better or worse than using an external processor?

Maybe a better buy is the RS10 with an external processor, especially if the extra on/off contrast ratio of the RS20 does not make much of a difference.

Tom, I am not sure what you are referring to as actual numbers in your 11%. Since the vector from D65 to REC709 Red (.640,.330) is .327, an 11% error would be .036. From that lets say Red is .670, .330 (x,y). Now, it is said a color error of .004 is visible. From that, .327 is 900% of a potentially visible error.

Now for luminance, say Red is supposed to be 15fL, the 11% error would be 13.35fL. At a gamma of 2.2, that would be the difference between 100 IRE and 95 IRE.

Now if you put your blocks on a screen with some separation, say opposite corners on a black, gray, white field, you could see the color difference, but might not be able to see the luminance difference.

I don't think you canuse a direct correlation to the digital 0-255 colors and luminance to what you see on a video display with respect to color space and luminance without the effects of signal and gamma. This is because if you use 11% luminance as a difference in linear digital 255 > 227 is about 11%, however digital 227 signal with a gamma of 2.2 would be about 11.6fL = 22.6%

The when we view on our PCs, no telling what gamma is in use there.......

JeffY - looks like you did nice work with the colors! Regarding attempt 2 - can you please reply or PM me with the settings you used for Color, and the individual CMS settings for RGBCYM? I'd like to quickly throw these into the RS20 and see how it looks at first glance. I'm sure settings used from another pj will not be ideal, but it'll be a great starting point to at least see at a glance what the colors look like and what perceivable error there is. I am optimistic given that green oversaturation does not tend to bother me unlike red, which you easily tamed. I'll report back on this. Thanks!

All the colors are spot on on x,y except cyan, and dE for all colors is 3.5 or under, except cyan at 7.5.

Picture quality is great, I'm sure it could be further improved, but I'm satisfied with the results.
JeffY has posted encourraging results as well, although he is also using a lumagen. EDIT (sorry I missed JeffY's post above).

Thanks all for your help, especially to Tom Huffman for his great tutorial.

JeffY - looks like you did nice work with the colors! Regarding attempt 2 - can you please reply or PM me with the settings you used for Color, and the individual CMS settings for RGBCYM? I'd like to quickly throw these into the RS20 and see how it looks at first glance. I'm sure settings used from another pj will not be ideal, but it'll be a great starting point to at least see at a glance what the colors look like and what perceivable error there is. I am optimistic given that green oversaturation does not tend to bother me unlike red, which you easily tamed. I'll report back on this. Thanks!

All the colors are spot on on x,y except cyan, and dE for al colors is 3.5 or under, except cyan at 7.5.

Picture quality is great, I'm sure it could be further improved, but I'm satisfied with the results.
JeffY has posted encourraging results as well, although he is also using a lumagen. EDIT (sorry I missed JeffY's post above).

These are the settings from your last calibration? ''Here are my settings (I'm aiming for about 12 fL with the iris at -15)

Contrast: -8
Brightness: 0
Color: -8
Tint: 0

(I recommend to set your gamma reference in the gamma menu before you work on the greyscale). I went for 2.3 which gave an average or just above 2.2.

Thanks Jeff. Did you use a test pattern for setting Brightness? With the PS3 I'm getting -6 or -7 for the
Brightness level from some dark patterns (like the AVS Blu-ray test disc). If you put up an all black image and then hit the "Hide" button, does the image change?

Thanks,
Darin

This is the AV Science Forum. Please don't be gullible and please do remember the saying, "Fool me once, shame on you. Fool me twice, shame on me."

I didn't try the hide button thing, but yes I used a test pattern. I find the correct brightness value tends to depend a lot on RGB offsets and gains.

I agree, but I didn't see any values for changes to RGB gains (which largely take the place of Brightness since it does basically the same thing for all 3 at once). When you said, "Color Temp 6500 (calibrated)" did you mean that you selected the 6500 preset or that you went in an adjusted the gains and offsets to get to 6500 yourself? If the latter it would be useful to see those numbers too.

--Darin

This is the AV Science Forum. Please don't be gullible and please do remember the saying, "Fool me once, shame on you. Fool me twice, shame on me."

I have slightly changed things now, I was using 6500k and just adjusting the offsets (can't change gains in 6500K), using custom gamma and doing the final grey scale adjustment on the Lumagen. Now I'm using 7500K, smaller offset changes and making the final adjustment on the Lumagen. It's easier to bring the blue levels down a bit than adjusting upwards especially at 100IRE.

All the colors are spot on on x,y except cyan, and dE for all colors is 3.5 or under, except cyan at 7.5.

Picture quality is great, I'm sure it could be further improved, but I'm satisfied with the results.
JeffY has posted encourraging results as well, although he is also using a lumagen. EDIT (sorry I missed JeffY's post above).

Thanks all for your help, especially to Tom Huffman for his great tutorial.

Bravo Manni!

This was what I was looking to see. I would be very happy with what you have accomplished. What was your approach?

Now instead of being stuck in New Orleans, I am stuck in Boston but I hopefully will be home tonight and my RS20 awaits.